1. Field of the Invention
The present invention relates to a socket for an electrical part for testing or inspecting a performance of an electrical part such as semiconductor device, which will be called hereinlater “IC package”.
2. Related Art
There is known an IC socket, as such a socket for electrical part, for accommodating an IC package as an electrical part, for example, as disclosed in the Japanese Laid-open Patent Publication No. JP H11-26126-A.
In this known example, the IC package is provided with a number of solder balls, as terminals, projecting downward from the lower surface of the IC package so as to provide a grid (lattice) arrangement having vertical and horizontal rows or lines.
On the other hand, the IC socket comprises a socket body to which the IC package is mounted and accommodated, a number of contact pins arranged to the socket body to be contacted to the terminal of the IC package, a movable member movably provided for the socket body to elastically deform the contacts pins so as to be contacted to or separated from the terminals of the IC package, and a cover for moving the movable member by means of lever member.
In an operation, when the cover is moved downward, a force applied portion of the lever member is depressed and is rotated about a shaft penetrating the movable member, so that the socket body is pressed downward by a force support (fulcrum) portion on the lower end side of the lever member. Therefore, the shaft acts as force applying (functioning) portion and moves parallelly horizontally in one direction to thereby move the movable member.
According to the movement of the movable member, the contact pins are pressed and elastically deformed to thereby open a pair of contact portions of each contact pin and then to insert the solder ball of the IC package into a gap between the opened contact a portions.
On the contrary, when the cover is moved upward, the pressing force of the movable member applied on the contact pins is released, and the contact portions of each of the contact pins return toward their initial closed positions to thereby clamp the solder ball therebetween and establish an electrical connection therebetween.
In the conventional structure mentioned above, however, the shaft (as force applying portion) of the lever member is provided so as to penetrate one end side of the movable member, i.e., the rear end side portion in the moving direction at the opening of the contact portions of the contact pin, so that when the pressing force is applied to the movable member through this shaft, the force applying direction of this pressing force is not necessarily horizontal with respect to the movable member. Accordingly, in the case where such pressing force is applied to the end portion of the movable member, the other end portion thereof maybe lifted, i.e., floated, which may lead to a trouble of an unstable attitude of the movable member, thus being inconvenient.